Specialty additives

A wide variety of chemicals may be added to impart specific properties to a rubber. These include the following types  

The term process aid is a general description for any material that will improve one or more aspects of the processing behaviour of rubber. These materials generally improve the flow behaviour, providing smooth surface finish to calendared or extruded products. Typical process aids include the following material types  

Fatty acids Emulsified esters Polyethylenes Liquid polymers 

Many additives aid the release of rubber compound from the steel processing equipment used for processing. The materials used are often chosen for their effectiveness in specific polymer types and include the following  

Fatty acids and soaps Emulsified fatty-acid esters 

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Figure 1.1 describes the interrelationships between the players in plastic materials manufacturing, which is considerably more complex than for the coating industry. The product performance specifications are defined by the end-users. Specialty additives demand is nowadays migrating to compounders, converters and distributors. 

Lubricants are formulated products composed of a base stock, which is either a mineral or synthetic oil, and various specialty additives designed for specific performance needs. Additive levels in lubricants range from 1 to 25% depending on the application. Synthetic base stocks are oligomers of small molecules, synthesized to a defined molecular weight. Important performance indicators include viscosity index which measures the viscosity index behavior over a temperature range, oxidative stability, and pour point. The performance of synthetic and mineral oils (Morse, 1998 Shubkin, 1993) is summarized in Table 2.7. 

Many industrial free-radical polymerization processes have been developed and commercialized for a variety of monomer and polymer types. A variety of monomers and polymerization processes have been commercially exploited. Further, there have been significant developments in synthesizing polymers with controlled architectures using free-radical polymerization during the last two decades. Materials synthesized include block copolymers, graft copolymers, and radial polymers. These materials find use in many common industrial and household applications such as adhesives, paints and coatings, textiles, nonwoven fabrics, personal care products, wallpaper, construction materials, specialty additives, and many other areas. 

M Chemicals, Specialty Additives, 3M Center building 223-6S-04, St. Paul, MN 55144-1000, USA... 

Specialty additives that are primarily acetylenic alcohols and amines... 

Tanatex Nostick. [Sybron] Specialty additive to prevent polymer buUdup on dry cans w equip. 

Fibers are delivered as pulps, which are chopped and refined hhers with a high surface area. The pulps are used as specialty additives that enhance performance hy providing excellent reinforcement. Lightweight strength reinforcement can he achieved with continuous filaments. Honeycomb cores are available for aerospace industries. Spun yarn is used for protective coatings. ... 

Plastic lumber is recycled plastics processed such as commingled plastic, polyethylene plastic, and polypropylene plastic. To improve their performances different developments have been used such as specialty additives (lubricants, deoxidizers, etc.). An example is by adding as low as 10 wt% of short glass fiber to these recycled plastics can double their strength. Other fibers used include hemp, flax, and sisal. They are principally extruded other processes are used such as injection and compression molding, to produce products competitive to wood lumber on land and in the water. Compression molding allows for a deep-molded grain and a much more dense board. The density also helps the product resist moisture absorption and improves weatherability. 

TPEs usually require little or no compounding with other materials. They are available fuUy compounded and ready for a wide range of uses. Their compositional consistency is higher than that of thermoset mbbers, which must be mixed with curatives, stabilizers, processing aids, and specialty additives such as flame retardants. 

The term filler is very broad and encompasses a very wide range of materials. We arbitrarily define in this book as fillers a variety of natural or synthetic solid particulates (inorganic, organic) that may be irregular, acicular, fibrous or flakey and are used in most cases in reasonably large volume loadings in plastics, mostly thermoplastics. Continuous fibers or ribbons are not included. Elastomers are also not included in this definition as well as many specialty additives that are used at low concentrations (e.g. pigments, lubricants, catalysts, etc). 

Freedonia s prediction for the sale of specialty additives in the USA imder the three above-mentioned categories is illustrated in Figure 6.1 below. The likely total market in 2006 for specialty additives was predicted to be 2.5 M toimes/y, worth US 5.9 billion. This imphes a growth rate of 3.7%/y by volume and 4.9%/y by value between 2001 and 2006. 

Data source Freedonia, Specialty Additives Study, October 2002... 

Cookson Specialty Additives, 1000 Wayside Road, Cleveland, OH 44110, USA tel +1-216-531-6010 fax +1-216-486-6638... 

This list is not by any means exhaustive but does give some idea of the complexities involved in formulating rubber products. Many other specialty additives may be added according to the requirements of the application. 

Many of these materials may be considered to be specialty additives but the volume of material required for efficacy requires that their properties as fillers (especially the effect on reinforcement) be given significant attention. 

Transmet Corporation, 4290 Perimeter Drive, Columbus, OH 43228, USA Toho Rayon Co., Ltd., 3-9 Nihonbashi 3-ehome Chuo-ku, Tokyo 103, Japan 3M Chemicals, Specialty Additives, 3M Center building 223-6S-04, St. Paul, MN 55144-1000, USA... 

You are employed at a chemical company and have recendy been transferred from a plant that manufactures synthetic dyes to a new facility that makes specialty additives for the polymer resin industry. 

A major trend the ETPs is enhancing performance by various routes such as modification via copolymers, blends and alloys, thermoplastic composites, and specialty additives. 

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